The invention disclosed and claimed herein deals with a novel process of preparing hydroxy functional vegetable oils and the vegetable oils so prepared.
Vegetable oils have been familiar to man since prehistoric times and for centuries, humans have used fats and oils for food and a variety of other uses. Humankind has over the years perfected the science surrounding the ability to produce oils from agriculture products for their own use. Today, millions of pounds of such oils are used in a variety of end use applications.
Vegetable oils are made up principally of triglycerides containing both saturated and unsaturated moieties, wherein the predominant moiety is the unsaturated variety. Even though the triglycerides lend themselves to many end use applications, there are some needs for these materials to have functionalities different than those that are found in the raw vegetable oil.
For example, the triglycerides can be converted to hydroxy functional compounds and the hydroxyl functional compounds can then be made useful, for example, in the formation of urethanes by reacting the hydroxyl groups with isocyanates. Coatings, adhesives, elastomers, foams and composites can be made from elastomers using such hydroxyl functional compounds. Unfortunately, some commercially available soy-based hydroxy functional compounds suffer from having an unpleasant odor that is often compared to stale French fries or old, used cooking oil. This odor transfers into articles made from such compounds, especially foam articles. This unpleasant characteristic of known soy-based polyols is one factor that has hindered their commercial success in polyurethane manufacturing.
Another issue that has hindered commercial success of soy-based polyols is that prior known soy polyols are not freeze/thaw stable. Even simple cooling of the oil down to about 10° C. will start the process of visible solids precipitating out of the oil. Actually freezing the oil only accelerates this process. After warming back up to ambient temperatures, the small, particulate solids driven out of the oil remain visible to the naked eye. With heat and stirring, the solids can be made to go into solution again. However, unless specifically removed, or re-dissolved, these solids could be expected to present downstream handling problems such as filter, valve and orifice plugging. If vegetable oil based polyols can be produced that sustain freeze/thaw stability, then subsequent handling problems could be essentially eliminated.
Currently, triglycerides are hydrolyzed with water that is catalyzed by enzymes, acids, or metals to yield glycerol products, that is, where the ester groups are removed and replaced with carboxyl moities. Such molecules still have unsaturation in them even after such treatment.
Fringuelli, and co-workers, have reported on a process to convert alkenes into 1,2-hydroxy groups using peroxy acids in deionized water. The process involves the epoxidation of the alkene, and then the epoxide ring is directly opened by organic acid and water, or via base hydrolysis to produce the hydroxy. It is stated by Fringuelli, et al that the synthesis does not require organic solvents. (Friguelli, F., Germani, R., Pizzo, F. and Savelli, G., ONE-POT TWO-STEP SYNTHESIS OF 1,2 DIOL, Synthetic Communications, 19(11 & 12), 1939-1943 (1989).
What has been discovered herein is a simple, economical preparative process for the provision of hydroxyl functional polyols that are derived by converting the alkene groups of the unsaturated molecules that make up vegetable oils, into hydroxyl groups. Furthermore, the polyols according to the invention overcome deficiencies of known products and processes by providing a non-malodorous, freeze/thaw stable product, among other benefits.